The present invention relates to a lamination structure including a hollow plate made of a thermoplastic resin and a metal late bonded to the hollow plate, and to a method for manufacturing the lamination structure.
A conventional hollow plate is known that has a plurality of cells each having the shape of a polygonal or cylindrical column. For example, Japanese Laid-Open Patent Publication No. 2010-247448 describes a hollow plate including a core layer in which a plurality of cells each having the shape of a hexagonal column is arranged. The core layer is formed by folding a sheet member that is made of a thermoplastic resin and has a predetermined shape. A superficial layer, which is a sheet member made of a thermoplastic resin, is bonded to each of the upper and lower sides of the core layer. The hollow plate is planar as a whole.
Further, a lamination structure is known in which metal plates are bonded to the hollow plate described above to improve the strength and appearance. For example, Japanese Laid-Open Patent Publication No. 10-156985 describes a composite plastic structure of high strength and rigidity that is manufactured by bonding a metal plate, which may be made of steel, stainless, or aluminum, to one or both sides of a hollow plate, which is made of a thermoplastic resin. Such a lamination structure may be manufactured by placing a metal plate on the upper surface of the hollow plate and pressing the metal plate from above with a heated jig to thermally fuse the hollow plate to the metal plate.
In this method for thermally fusing the hollow plate to the metal plate, the heated jig heats the superficial layer of the hollow plate through the metal plate. This process requires time to heat the metal plate and the superficial layer to adequate temperatures. Thus, when the superficial layer melts, the core layer of the hollow plate is also heated and melted. This softens the core layer in the middle section in the thickness direction of the hollow plate, causing the cell structure of the hollow plate to be easily compressed by the pressing pressure during thermal fusion. The strength of the lamination structure is therefore reduced.